Effect of Powder Characteristics on Slip Casting Fabrication of Dental Zirconia Implants

2020 ◽  
Vol 20 (9) ◽  
pp. 5385-5389
Author(s):  
Woo Chang Kim ◽  
Jong Kook Lee
Keyword(s):  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Close Packing ◽  
Solid Loading ◽  
Characteristic Analysis ◽  
Yttria Content ◽  
Powder Characteristics ◽  
Powder Type ◽  
Zirconia Implants ◽  
Zirconia Powders

Dense zirconia compacts were fabricated by slip casting and sintering of nanoscale zirconia powders, and the effect of the powder characteristics (crystallite size, specific surface area, yttria content, and agglomeration) on the slurry and sintered properties was investigated. Three types of commercial 3 mol% yttria-stabilized tetragonal zirconia polycrystals powders were used as the starting powders after the powder characteristic analysis. A zirconia slurry for slip casting was prepared by mixing zirconia powder (solid loading of 60, 65, and 70 wt.%), distilled water, and a dispersant of Darvan C. The green compacts obtained from slip casting were cold isostatic pressed to enhance the close packing and densified by sintering at 1450 °C for 2 h. Highly dense zirconia compacts with a relative density of 99.5% and grain size of 350 nm were obtained based on the powder type and solid loading in the slurry. The microstructure and mechanical hardness of the sintered specimen after slip casting were dependent on the yttria content in the 3 mol% yttria-stabilized tetragonal zirconia polycrystal powder and the solid loading within the slurry.

Fabrication of an All-Ceramic Implant by Slip Casting of Nanoscale Zirconia Powder

2020 ◽  
Vol 20 (9) ◽  
pp. 5703-5706
Author(s):  
Dae Sung Kim ◽  
Jong Kook Lee
Keyword(s):  
High Surface ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Solid Content ◽  
Solid Loading ◽  
Forming Process ◽  
Surface Cracking ◽  
All Ceramic ◽  
Mechanical Machining ◽  
Zirconia Implants

Dental implants are typically composed of 3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals). Most dental zirconia implants are currently fabricated via mechanical machining. However, during the machining of zirconia green bodies, many cracks form on the surface. To prevent surface crack formation on the implants, shape forming of the zirconia is necessary using methods such as slip casting. Herein, we fabricated green compacts using slip casting, candidate forming process to reduce surface cracking. To fabricate an optimal 3Y-TZP implant by slip casting and sintering, we prepared a suitable 3Y-TZP slurry for slip casting by adjusting the viscosity via pH, dispersant agent content, and solid loading refinement. Green compacts were prepared by the slip casting of all-ceramic zirconia implants fabricated using optimal slurry conditions, for example, 60 wt% solid content, 1 wt% dispersant, pH 12 and post-sintering at 1450 °C for 2 h. All sintered bodies contained a tetragonal phase with a high sintered density of approximately 6.07 g/cm3, good mechanical hardness of approximately 1367 Hv, grain size of 220 nm, and high surface roughness without cracks.

Preparation of Bimodal Porous Apatite Ceramics through Slip Casting Using Fine Hydroxyapatite Powders

2006 ◽  
Vol 317-318 ◽  
pp. 723-728 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Flexural Strength ◽  
Size Range ◽  
Slip Casting ◽  
Fine Powder ◽  
Total Porosity ◽  
Solid Loading ◽  
Wet Milling ◽  
Hydrogen Phosphate ◽  
Optimum Amount ◽  
Porous Hydroxyapatite

A bimodal porous hydroxyapatite (HAp) body with high flexural strength was prepared through slip casting. HAp fine powder used in this study was synthesized by wet milling, drying and heating of a mixture of calcium hydrogen phosphate di-hydrate and calcium carbonate. The synthesized HAp powder was 0.320.05 μm in size and 38.10.8m2/g in specific surface area. The slip was prepared by adding deflocculant and foaming reagent. The optimum value for the minimum viscosity in the present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were studied. The total porosity of the specimens obtained from a slip of 48 wt% HAp solid loading is in the range of 49 – 61vol %, and the resultant porous HAp sintered body had large spherical pores of 300 -m with interconnecting rectangular voids. Many small pores in the size range of 2-3 -m or below were observed in the specimen obtained by heating at 1100, and 1200 . The flexural strength of the bimodal porous HAp ceramics sintered at 1200 C showed a large value of 17.6 MPa, with a porosity of 60.5vol.

Effect of Sintering Temperature on the Mechanical Properties of Nanostructured Ceria-Zirconia Prepared by Colloidal Process

2015 ◽  
Vol 1125 ◽  
pp. 401-405
Author(s):  
Mohamed M. Aboras ◽  
Andanastuti Muchtar ◽  
Noor Faeizah Amat ◽  
Che Husna Azhari ◽  
Norziha Yahaya
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Slip Casting ◽  
Tetragonal Zirconia ◽  
Cold Isostatic Pressing ◽  
Sintering Process ◽  
Colloidal Processing ◽  
Tooth Color ◽  
Biological Compatibility ◽  
Nanostructured Ceria

The demand for tetragonal zirconia as a dental restorative material has been increasing because of its excellent mechanical properties and resemblance to natural tooth color, as well as its excellent biological compatibility. Cerium oxide (CeO2) has been added to yttria-stabilized zirconia (Y-TZP), and studies have demonstrated that the stability of the tetragonal phase can be significantly improved. Y-TZP with 5wt% CeO2 as a second stabilizer was developed via colloidal process, followed by a suitable sintering process. According to the literature, the sintering process is the most crucial stage in ceramic processing to obtain the most homogeneous structure with high density and hardness. This study aims to investigate the effect of sintering temperature on the mechanical properties of nanostructured ceria–zirconia fabricated via colloidal processing and slip casting process with cold isostatic pressing (CIP). Twenty-five pellet specimens were prepared from ceria–zirconia with 20 nm particle size. CeO2 nanopowder was mixed with Y-TZP nanopowder via colloidal processing. The consolidation of the powder was done via slip casting followed by CIP. The samples were divided into five different sintering temperatures with. Results from FESEM, density and hardness analyses demonstrated statistically significant increase in density and hardness as the sintering temperature increased. The hardness increased from 4.65 GPa to 14.14 GPa, and the density increased from 4.70 to 5.97 (g/cm3) as the sintering temperature increased without changing the holding time. Sintering Ce-Y-TZP at 1600 °C produced samples with homogenous structures, high hardness (14.14 GPa), and full densification with 98% of the theoretical density.

scholarly journals Fracture Resistance of Zirconia Oral Implants In Vitro: A Systematic Review and Meta-Analysis

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 562 ◽  
Author(s):  
Annalena Bethke ◽  
Stefano Pieralli ◽  
Ralf-Joachim Kohal ◽  
Felix Burkhardt ◽  
Manja von Stein-Lausnitz ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Static Loading ◽  
Fracture Resistance ◽  
Tetragonal Zirconia ◽  
Present Review ◽  
Hydrothermal Aging ◽  
Oral Implants ◽  
Electronic Screening ◽  
The Impact ◽  
Zirconia Implants

Various protocols are available to preclinically assess the fracture resistance of zirconia oral implants. The objective of the present review was to determine the impact of different treatments (dynamic loading, hydrothermal aging) and implant features (e.g., material, design or manufacturing) on the fracture resistance of zirconia implants. An electronic screening of two databases (MEDLINE/Pubmed, Embase) was performed. Investigations including > 5 screw-shaped implants providing information to calculate the bending moment at the time point of static loading to fracture were considered. Data was extracted and meta-analyses were conducted using multilevel mixed-effects generalized linear models (GLMs). The Šidák method was used to correct for multiple testing. The initial search resulted in 1864 articles, and finally 19 investigations loading 731 zirconia implants to fracture were analyzed. In general, fracture resistance was affected by the implant design (1-piece > 2-piece, p = 0.004), material (alumina-toughened zirconia/ATZ > yttria-stabilized tetragonal zirconia polycrystal/Y-TZP, p = 0.002) and abutment preparation (untouched > modified/grinded, p < 0.001). In case of 2-piece implants, the amount of dynamic loading cycles prior to static loading (p < 0.001) or anatomical crown supply (p < 0.001) negatively affected the outcome. No impact was found for hydrothermal aging. Heterogeneous findings of the present review highlight the importance of thoroughly and individually evaluating the fracture resistance of every zirconia implant system prior to market release.

Effect of microscale shear stresses on the martensitic phase transformation of nanocrystalline tetragonal zirconia powders

2010 ◽  
Vol 30 (13) ◽  
pp. 2749-2755 ◽  
Author(s):  
Mette Skovgaard ◽  
Anwar Ahniyaz ◽  
Bent F. Sørensen ◽  
Kristoffer Almdal ◽  
Alexander van Lelieveld
Keyword(s):  
Phase Transformation ◽  
Tetragonal Zirconia ◽  
Martensitic Phase ◽  
Martensitic Phase Transformation ◽  
Shear Stresses ◽  
Zirconia Powders

Preparation of Complicated SiC Green Bodies via Aqueous Slip Casting

2010 ◽  
Vol 434-435 ◽  
pp. 88-91
Author(s):  
Yuan Li ◽  
Ji Qiang Gao ◽  
Jian Feng Yang
Keyword(s):  
Particle Size ◽  
Slip Casting ◽  
Solid Loading ◽  
Reaction Sintering ◽  
Processing Parameter ◽  
Suspension Viscosity ◽  
Effects Of Ph ◽  
Depth Study ◽  
Packing Ability ◽  
Coke Powder

Two domestic silicon carbide powders with different particle size distribution and one petroleum coke powder were blended in proportion and then dispersed in aqueous medium. Green bodies were solidified from these suspensions via conventional slip casting. The effects of pH, solid loading, and the amount of dispersant on the formability and packing ability were evaluated. The results showed that the pH within 9.5-10.5, solid loading of 42vol%, aging time more than 24h, and 0.3wt% of dispersant were optimal. Complicated green bodies with height of 300mm and thickness of 3.5mm were obtained. The corresponding suspension viscosity was 1200mPa∙s and the relative packing density was 64.8%. The density is 3.01g∙cm-3 and the flexural strength is 305±15 MPa after reaction sintering. These results may be attributed to accurately using of dispersant and in-depth study of processing parameter.

scholarly journals Mechanical Investigation of a Novel Ceramic Composite Consisting of the YAG Matrix With Alumina Nanoparticles Fabricated by Slip Casting and the Conventional Sintering Process

2020 ◽  
Author(s):  
Mohammad Torki ◽  
behrooz movahedi ◽  
S S. ghazanfari ◽  
M. Milani
Keyword(s):  
Relative Density ◽  
Slip Casting ◽  
Ceramic Composites ◽  
Alumina Nanoparticles ◽  
Solid Loading ◽  
Sintering Process ◽  
The Matrix ◽  
Conventional Sintering ◽  
Mechanical Investigation ◽  
Composite Hardness

Abstract The aim of this study was to fabricate YAG/Al2O3 ceramic composites with different alumina nanoparticles using slip casting and the atmospheric sintering process. In addition, some mechanical properties such as hardness and elastic modules of this novel ceramics were evaluated using the nanoindention technique. The results showed that the rheological behavior of the slurry was optimized to the solid loading of 55 wt% and the relative density of the green body was enhanced up to 65%. Relative density was increased after sintering at 1700 °C for 12 h to 99.5% and the pore size (150 nm) was reduced to half of that of powder particles. It should be noted that the optimum amount of alumina nanoparticles as a reinforcing agent in the matrix was less than 5%wt and the composite hardness was increased to 7.3%, as compared to the pure YAG ceramic.

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